- Actually, fully, installed OpenJDK. The mistake I was making here is that Ubuntu LOOKED like it installed OpenJDK, but it didn't actually finish the installation until I ran:
- Install Netbeans, using the OpenJDK installed in step #1.
I have no idea WHY the Oracle JDK failed Netbeans, but it seems like this is a fairly common problem. Hopefully this post will help other people avoid the same dark fate as my lost three hours.